The Health Sciences Center of the University of Illinois at Chicago (UIC), is a major medical center with large and productive departments in the medical and health-related sciences. At least thirty-five research programs at this Center, largely supported by NIH funds, are dependent on mass spectrometry (MS) for their research, and several are heavily dependent on such MS instrumentation. At present, two mass spectrometers service these research programs. In addition to one full-time, and another part-time operator, the two spectrometers also support approximately thirty hands-on users from the various research programs. The instruments are scheduled on an around-the-clock- basis (365 days/year) and yet, as much as half of the requested instrument time must be refused because of over subscription. In addition, a third, twenty-year old instrument, which served as the backbone of the organic medicinal chemistry and pharmacognosy research programs, recently had to be scrapped for lack of parts. Importantly, the present instrumentation does not provide for introduction and mass analysis of polar, high molecular weight substances. Biomedical research at UIC would be greatly facilitated by the ability to do mass analysis on a variety of peptides, DNA-adducts, natural products and synthetic derivatives falling in this category. Thus, present instrumentation is inadequate both quantitatively and qualitatively. To address these difficulties, we propose to acquire a medium level mass spectrometer equipped with, fast atom bombardment, thermospray-LC interface, GC interface, and higher mass range capabilities. The present MS work load (and overload) will then be integrated over the two existing spectrometers and the new instrumentation in such a fashion as to take advantage of the design characteristics of each. In combination with an additional Ph.D. level spectroscopist, provided by the University, such instrumentation will give UIC the equipment necessary to provide the needed mass analyses of polar, higher molecular weight substances, as well as provide sufficient instrument time to cover the present overload.